These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Kappa opioids inhibit induction of long-term potentiation in the dentate gyrus of the guinea pig hippocampus.
    Author: Terman GW, Wagner JJ, Chavkin C.
    Journal: J Neurosci; 1994 Aug; 14(8):4740-7. PubMed ID: 7913954.
    Abstract:
    NMDA receptor-mediated long-term potentiation (LTP) of dentate granule cell responses to perforant path stimulation was inhibited by the kappa 1 opioid receptor agonist U69,593. This inhibition was reversed stereospecifically by naloxone and blocked by the selective kappa 1 antagonist norbinaltorphimine (NBNI). NBNI, by itself, had no effect on LTP induced by threshold stimulation but significantly enhanced LTP from more prolonged stimulation. This effect of NBNI suggests that endogenous opioids can regulate LTP in the dentate gyrus. In support of this hypothesis, stimulation of dynorphin-containing fibers also blocked LTP production in an NBNI-sensitive manner. Finally, dynorphin-mediated inhibition of LTP acts primarily on mechanisms of induction rather than maintenance or expression, since dynorphin released immediately before, but not immediately after, perforant path stimulation blocked LTP. Thus, exogenous and endogenous kappa opioids can inhibit induction of long-term potentiation at the perforant path-granule cell synapse and may therefore regulate plastic changes in synaptic transmission in a brain region thought to play an important role in processes of both learning and memory and epileptogenesis.
    [Abstract] [Full Text] [Related] [New Search]